The present invention relates to a camera having a changeover mechanism capable of changing a photographing aperture size. The photographing aperture as defined here relates to the size of the opening (inside the camera body) directly in front of the film, that determines the size of the exposed area (and therefore the aspect ratio of the exposed area) of each frame of the film.
Recently, cameras have been developed that have changeover mechanisms for selecting a photographing aperture size from among: a standard size (large photographing aperture size), panorama size, half size (small photographing aperture size), and so on. Conventionally, this type of the camera includes a photographing lens system (photographing optical system) having a photographing lens, lens barrel or the like which retracts inward (i.e., toward the film side) when photographing is prohibited by turning OFF a power supply switch, or the like (when a photographing prohibition mode is set). In this type of camera, a drawback as described below arises. The photographing aperture size changeover mechanism has light shading plates (partial light shading members), and is disposed behind the rear group of photographing lenses. When a photographing prohibition mode is set, the position where the rear group of photographing lenses or the lens barrel for supporting the rear lens group is accommodated is restricted by the light shading plates. This is an obstacle for reducing the size and thickness of a camera.